With the development of Internet technology, more and more social activities have been transferred to the Internet, including extension of offline social activities on the internet, such as instant messenger products, social networks, etc., as well as social lives in a virtual world, such as online games and so on. Friend management is one of the most fundament and most important function of online social networking, e.g., friend noting, friend grouping, etc. Reasonable friend grouping will enable a user to easily identify and search for friends. Furthermore, reasonable friend grouping plays an even more important role when a user needs to specify different extent of permission to various groups.
Traditional solutions for friend grouping include manual grouping by a user, screening according to key words, and clustering through social networks, etc. Manual grouping by the user is relatively laboursome and, as known by experience in social networks, many users are not enthusiastic about noting and grouping their friends. As a result, it becomes difficult for a user to identify or group a friend as friends accumulate. On the other hand, screening by key words relies on the key words given by a user to her/his friends, e.g., college, city, and company, etc., which limits the application of this solution to social networks with a real-name system and requires highly accurate key words. Yet in fact, it is almost impossible for virtual social networks, such as instant messenger products, to keep strict conformance in key words. Moreover, since consistent key words are required, it is necessary to pre-define key words, which costs time and labor.